Coal is a sedimentary rock that people burn for fuel, which is then used to generate electricity. It is composed mostly of carbon and hydrocarbons. Burning (or combusting) coal releases the energy stored in the chemical bonds of these carbons and hydrocarbons. Coal is a fossil fuel, meaning it forms from the remains of ancient organisms. Millions of years ago, remains of plants and algae sunk to the bottom of wetlands. Throughout that time, new vegetation and mud gathered on top of these remains and compressed them. As these remains were compressed and heated by high temperatures in the earth, they developed into peat (a sponge-like substance containing partially decomposed plants), and then later into coal. Both peat and coal have high levels of carbon.

Because coal takes millions of years to develop, there is a limited amount of it, making coal a nonrenewable resource. Further, like all fossil fuels, burning coal causes a chemical reaction with the air that releases carbon dioxide emissions into the atmosphere. Carbon dioxide is a greenhouse gas, meaning it traps the sun’s heat in Earth’s atmosphere and contributes to human-caused climate change.

People extract coal from the ground through surface mining, which happens over a wide area of land but close to the surface, and underground mining, which requires drilling deep into the ground. It is often found in long strips called seams. There are coal reserves all over the world, with the largest reserve, nearly 250 billion tonnes, in the United States. Russia, Australia and China also each have over 100 billion tonnes of coal underneath their land. China is the biggest coal provider, accounting for around half of the world’s yearly coal production.

In 2025, global coal consumption reached an all-time high, at nearly 9 billion metric tons, although the International Energy Agency predicts this demand will decline by 2030. Much of this coal was used to produce electricity, meeting about 35% of the world’s electrical demands. Manufacturing also uses coal, particularly in China, which is the largest global consumer of coal. India is also a growing user of coal. However, statistics about these countries’ coal usage can mask other countries’ usage. For example, while the United States and Europe have reduced their reliance on coal and started to use other renewable energy sources, they also rely on products manufactured in Chinese factories that run on coal, such as electric vehicle batteries.

Positives and Negatives of Coal

There are many reasons why coal is a popular energy source worldwide. First, it exists in many areas. In areas that lack access to infrastructure, coal is useful in the home as well as in industry. Around 2 billion people worldwide use coal and other solid fuels for cooking, particularly in rural areas. Additionally, coal is easy to store and transport compared to other fuels.

However, there are many drawbacks to using coal for fuel. Firstly, all types of coal mining are harmful to the environment. Coal mines are a significant source of methane gas and carbon dioxide in the atmosphere, which worsens climate change. Mining also releases heavy metals that pollutes rivers, groundwater and other water sources, where the toxic metals can harm both human and wildlife health. For example, a now-abandoned coal mine in Alberta Canada’s Elk River Valley has leached heavy metals into the surrounding ecosystems. The fish in the valley’s waterways have raised levels of the metal selenium in their bodies and often birth deformed young or don’t birth young at all.

Land disturbance is also frequent with mining; mining companies destroy or seriously harm habitats to build surface mining operations, and areas with underground mines have experienced sinkholes and other kinds of land collapse due to tunneling. In the United States, land collapse is common in heavily mined areas like Western Pennsylvania; in 2024, a woman from that area died after a mine collapse created a sinkhole near her home.

Coal mining can also be harmful to individuals working in mines. First, working in a coal mine is incredibly dangerous, with mine roofs caving in, spontaneous combustion of coal and the potential for many other kinds of physical injuries. Methane, which is released by coal production, can build up in mines that are not properly ventilated and then, if ignited, explode. This can happen when work is abandoned in one part of a mine but the area is not properly sealed off, allowing the methane to leak into work areas. Mine collapses are another major hazard; in Inner Mongolia in 2023, at least six people died and 47 people went missing in a mine collapse, exacerbated by landslides that delayed rescue efforts. An even more staggering loss of life happened in Soma, Türkiye, in 2014, when 301 miners died in an explosion.

There are also long-term health effects from working or living near a coal mine. Exposure to coal dust from mining contributes to several major causes of death in the United States, including cancer and respiratory diseases like chronic obstructive pulmonary disease, or COPD. About 10–20% of coal workers in the United States get a disease called coal workers’ pneumoconiosis—informally called black lung disease—through exposure to coal dust. Research has shown that people who live near mines are exposed to coal-related pollution that can have health effects decades later, even for those who did not work in the coal industry.

Marginalized communities are often the most affected by pollution and hazards from coal mines. In some cases, it is because coal mines were set up in lands that formerly belonged to Indigenous people. This is the situation in Colombia, where Indigenous minorities like the Wayúu community are fighting coal companies who are taking away their access to their ancestral, spiritually significant land. The Wayúu have launched many protests to stop the coal companies, and their activism has led to some victories. In 2019, the Colombian Constitutional Court recognized that the major coal company in the region violated the Wayúu’s rights to health and a healthy environment. But the Wayúu are still fighting to have officials enforce this ruling.

Additionally, coal mines are often built in rural communities with limited infrastructure and access to resources and opportunities. Over time, the people in those communities come to rely on the coal mines financially, while being harmed by the mine’s impact on the environment, people’s health and the local economy. Despite having access to work at the mine, these communities largely still experience poverty. This is the case in the Appalachian region of the United States, where the combination of poverty and environmental pollution has led to poor health outcomes for the community, with areas close to coal mines experiencing higher levels of heart disease.

Lastly, while coal is found all over the world, the supply is shrinking. The estimates for how long the world’s coal supply will last vary widely, but most say it will last roughly 100 years or more (in comparison, the world’s oil supply is only expected to last another 30–50 years).

Types of Coal

The four main types of coal are ranked by how dense they are and how much carbon they contain; the higher the carbon content, the higher the purity of the coal. Anthracite is the most carbon-rich coal, which gives it the highest heating value and the most energy availability, making it the top-ranked coal. The next highest ranked is bituminous, which also has a high heating value, though lower than anthracite. Subbituminous coal has a much lower heating value and is ranked third in coal quality. The lowest quality coal is lignite, which has the lowest amount of carbon. There is research that shows lignite is more harmful to both the environment and people’s health when compared to coal that contains more carbon, because lignite contains other harmful chemicals, such as mercury.

Coal Mining

Coal is mined through two general processes: underground mining and surface mining. Surface mining extracts coal that is less than about 60 meters (nearly 200 feet) below the surface of the ground. It involves removing soil and rock layers, and sometimes even the tops of mountains, to get to coal seams. Underground mining uses shafts and tunnels to get to coal seams more than 60 meters below ground, sometimes reaching depths of thousands of meters. The deepest coal mine in the world is the Shakhterskaya, located in Donbass, Ukraine, which goes more than 1,500 meters (4,921 feet) below the surface. Though both types of mining carry environmental and health risks, surface mining is considered safer, easier and less expensive than underground mining.

After miners use large pieces of machinery to remove coal from the ground, it can be sent to a preparation plant that rids the coal of impurities like dirt, rocks and other minerals. Then trains, ships and other transportation vehicles deliver coal around the world.

History and Uses of Coal

Humans have used coal as a fuel source for a very long time, perhaps for thousands of years. There is evidence that people in ancient China were mining for coal in an organized fashion as many as 3,600 years ago. It was likely burned to heat homes. The Industrial Revolution in the 19th century saw a big jump in coal use, where it powered factories, steam engines and processes to create other metals. The pollution caused by the unchecked use of coal during this time period had grave consequences. Several studies suggest that industrial coal use led to a higher infant mortality rate. Today, coal is still used in electricity generation across the world. In some countries, coal makes up a sizable percentage of their fossil fuel usage. For example, until recent years, more than 50% of China’s energy generation regularly came from coal. In India, coal accounts for about three-quarters of electricity generation.

Because coal production and use harm the environment and human health, many countries are reducing their use of coal and the amount of coal their country produces. In 2024, government energy leaders from the G7 countries—Canada, Germany, the United Kingdom, the United States, France, Japan and Italy—agreed to invest in renewable energy sources instead of coal. They also pledged to shut down coal-burning power plants that don’t capture carbon dioxide before it goes into the atmosphere by 2035. Possible energy sources to replace coal and better protect the environment should be renewable, such as hydropower, which produces energy through the natural movement of water. Another option is biomass from waste materials like sewage, which can be burned for energy. Biomass fuels can be used in ways similar to coal and work with similar power-generation equipment, but unlike coal, they are renewable.